Power operated fluid infusion device

ABSTRACT

A portable, power operated fluid infusion device is disclosed for automatically, intraveneously administering a drug to a patient. The device comprises a housing which contains a mechanically operated timing mechanism, a rack in engagement with a pinion rotated by the timing mechanism, and spiral springs for longitudinally urging the rack in a forward direction. Attached to the forward end of the housing in axial alignment therewith and with the rack is a syringe which has an internal axially movable piston that is coupled to and longitudinally moved by the rack. The springs assist the slowly rotating pinion to positively move the rack, and hence the piston, in a longitudinal direction thereby permitting a controlled amount of the drug to be automatically expelled from the syringe over an extended period of time.

United States Patent 1 Szabo et a1.

3,886,938 June 3, 1975 1 1 POWER OPERATED FLUID INFUSION DEVICE [75]Inventors: Anthony W. Szabo, Livingston, N..l.;

Louis R. M. Del Guercio, Larchmont, NY.

[73] Assignee: Anthony Scala, Livingston, NJ. a

part interest [22] Filed: Oct. 23, 1973 [21] Appl. No; 408,264

[52] US. Cl 128/218 A; 128/214 F; 128/218 F [51] Int. Cl A6lm 5/20 [58]Field of Search 128/218 A, 218 F, 215, 128/234, 214 F, 218 R, DIG. l,DIG. 12, 214 R; 222/386 [56] References Cited UNITED STATES PATENTS2,498,672 2/1950 123/218 A 2,531,267 11/1950 Harnisch 128/218 F2,605,765 8/1952 Kollsman 128/218 F 2,671,448 3/1954 Harnisch 128/218 F3,384,080 5/1968 Muller..................... 128/214 F 3,701,345 10/1972Hellman et a1. 128/218 A 458,275 7/1950 Italy 128/218 A PrimaryExaminer-Richard A. Gaudet Assistant Examiner.l. C. McGowan Attorney,Agent, or Firm-Larson, Taylor and Hinds [57] ABSTRACT A portable, poweroperated fluid infusion device is disclosed for automatically,intraveneously administering a drug to a patient. The device comprises ahousing which contains a mechanically operated timing mechanism, a rackin engagement with a pinion rotated by the timing mechanism, and spiralsprings for longitudinally urging the rack in a forward direction.Attached to the forward end of the housing in axial alignment therewithand with the rack is a syringe which has an internal axially movablepiston that is coupled to and longitudinally moved by the rack. Thesprings assist the slowly rotating pinion to positively move the rack,and hence the piston, in a longitudinal direction thereby permitting acontrolled amount of the drug to be automatically expelled from thesyringe over an extended period of time.

2 Claims, 5 Drawing Figures PATENTEDJUH 3 I975 SHEEY h U h 1 POWEROPERATED FLUID INFUSION DEVICE BACKGROUND OF THE INVENTION 1. Field ofthe Invention This invention relates to portable, automatic fluidinfusion devices and more particularly to a low pressure. highlyreliable, completely mechanically driven infusion syringe device whichpermits automatically controlled drug infusion over an extended timeperiod.

2. Description of the Prior Art In a modern hospital complex, medicalpersonnel are increasingly being called upon to perform numerous, timeconsuming activities. Consequently, as constantly increasing demands aremade for the time of limited number of medical personnel, it has beenfound that the frequency of late performance or omitted performance ofthe more routine activities, such as the administering of injections,has increased. Certain illnesses, such as pulmonary embolas requiretreatment by administering daily numerous, periodic injections of thesame drug. By easing of the burden of repeatedly administering theseinjections by hospital personnel would provide more time for otheractivities. Furthermore, the omission of the delay in administering theinjections can in some cases result in serious consequences. Not only isthe frequent administering of the injections time consuming, it is alsoan additional expense for the patient.

One solution to the problem of having to frequently administerinjections has been to confine the patient to a bed and to administerthe medicine as a fluid with a gravity bed bottle system. The systemcomprises a bottle containing the fluid suspended above the patient, aneedle inserted into a vein or artery of the patient, and tubingconnecting the bottle to the needle. An obvious disadvantage of thebottle system is that it unnecessarily confines an other wise ambulatorypatient to a bed. Other disadvantages of the bottle system arenon-adaptibility for administering fluids to animals and non-capabilityof use with viscuous fluids.

There is prior art which attempts to remedy the aforementioned problemsby utilizing syringes that are operated by electrical motors. Initially,it was believed that devices that use small electric motors to operatelinkage which depresses the plunger of a standard syringe, wouldovercome all the aforementioned problems. However, these devices haveproven unsatisfactory for a number of reasons. Most importantly, it wasdiscovered that any introduction of electricity into the body, even onthe order of microamperes and irrespective of whether the electricity isAC or DC, can cause heart fibrillations. In addition, besides being veryexpensive, these devices are not reliable since a loss of power, eitherdue to a defective unit or a deenergized battery, would result in anundetectable inoperative device.

Thus, there is a need for a completely safe, nonelectrical,positiveacting, power operated syringe which is inexpensive and can beeasily worn on the arm or leg of an ambulatory patient or can bestrapped to the body of an animal. None of the known prior art deviceshave positive acting gearing mechanism for driving a memher to force aviscuous therapeutic drug fluid out of an infusion device.

SUMMARY OF THE INVENTION The present invention provides a highlyreliable, portable fluid infusion device that automatically discharges apredetermined amount of fluid continuously over an extended time period.Furthermore, the present invention is completely portable, light weight,attachable to an ambulatory patient or animal, and can be inexpensivelymade so that after its use it can be permanently discarded.

Included in the present invention is a housing, a syringe mounted on thehousing, the syringe comprising an elongated container having an orificein one end thereof and a piston mounted for longitudinal movement withinthe container for forcing a fluid stored in the container through theorifice. and a mechanical timing mechanism mounted on the housing. Thetiming mechanism includes a main spring, an escapement mechanism, agearing mechanism rotated by the main spring at a rate controlled by theescapement mechanism, a rotatable main shaft extending outwardly fromthe gearing mechanism and rotated thereby, the main shaft having apinion mounted on the outwardly extending end thereof, and a member forwinding the main spring of the timing mechanism. A rack engages thepinion of the timing mechanism and is integral with a longitudinallymovable member which is coupled to the piston of the syringe, therebylongitudinally moving the piston at a predetermined rate andconsequently forcing fluid at a predetermined rate through the orifice.The rack is urged in a longitudinal direction and into engagement withthe piston for the longitudinal movement of the latter by a spring, thepinion of the timing mechanism restraining the longitudinal movement ofthe rack to a predetermined rate which is determined by the rotationalspeed of the pinion.

Other features and advantages of the invention will be set forth in, orapparent from, the detailed description of the presently preferredembodiments thereof found hereinbelow.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings in which likereference numerals denote like elements:

FIG. 1 is a perspective view of a presently preferred embodiment of theinvention;

FIG. 2 is a front elevation view of the invention wherein one side ofthe housing has been removed for illustrating the internal partsthereof;

FIG. 3 is a longitudinal cross sectional view of the invention takenalong line 3-3 of FIG. 2;

FIG. 4 is a transverse cross sectional view taken along line 4-4 of FIG.2, and

FIG. 5 is a perspective view with part of the housing broken away of asection of a second embodiment of the invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT With reference to FIG. 1,a presently preferred embodiment of a fluid infusion apparatus 10 isshown according to the invention. Apparatus I0 is comprised of alongitudinally extending, rectangular housing 12 and a syringe l4removably mounted at one end of housing 12 in axial alignment therewithwith means such as mounting plate 16 and screws 18. A strap 20 isfixedly mounted on housing 12 and provides a means by which apparatus 10can be attached to a body portion ofa patient.

Syringe 14 is comprised of an elongated cylindrical container 22 havingan end 24 distal from housing 12. In distal end 24 is an orifice 26 forpermitting communication between the interior of container 22 and ahypodermic needle (not shown) which can be reniovably attached at distalend 24. An elongated piston 28 is mounted for longitudinal movementinside container 22. Piston 28 is comprised of a head section 32integral with an elongated shaft 30 which extends into the inside ofhousing 12. Head section 32 is divided into a forward section 34 and arearward section 36. Forward section 34 and rearward section 36 form anannular forward and rearward seal, respectively, with the internal wallof container 22. Consequently. piston 28 divides the internal volume ofcontainer 22 into a forward chamber 38 for containing a fluid which isto be injected into the patient, and a rearward section 39 which is keptfree from the fluid thrbugh the sealing action of forward section 34 andrearward section 36 of the piston head section 32. Container 22 ispreferably made of a transparent, nonporous material, such as glass or aplastic. It is common practice to have graduations, such as graduations40 in FIG. 2, etched or otherwise marked on the surface of container 22so that the amount of fluid remaining in the chamber 38, and theposition of piston 28 inside container 22 can be determined. Graduations40 can be marked off either in fluid volume or in time intervals of, forexample, every two hours.

Housing 12 of fluid infusion apparatus can conveniently be manufacturedin relatively small dimensions such as, for example, I by 1 inch squarein transverse cross section by two and a half inches long. In otherembodiments of the invention, the housing can have different transversecross sectional shapes, suchas rectangular or elliptical, and can havedimensions of, for example, three-quarter by 1 inch. Many, easilyavailable, strong, and light weight materials can be used for theconstruction of housing 12 and include, for example, aluminum, stainlesssteel, and certain polymer plastic materials. Housing 12 is comprised ofa forward end 42, a rear end 44, a front panel 46, a back panel 47, andlateral sides 48 which are removably mounted on ends 42 and 44 and frontand back panels 46 and 47 with means such as screws 49.

With reference to FIG. 2, there is shown a coupling member 50 attachedat a forward end to and in longitudinal axial alignment with shaft ofpiston 28. Member 50 extends through a seal 52 located in forward end 42of housing 12 and into the interior of housing 12. Rigidly mounted nearthe rearward end of coupling member 50 is a base 54 which extendstransversely to and slidably engages with sides 48 of housing 12. Base54 centers and maintains the axial alignment of coupling member 50 withpiston 28 in a first, transverse plane during the longitudinal movementof these components. As best shown in FIGS. 3 and 4, coupling member 50terminates at its rearward end in a collar 56 which has an axial borethat extends in the first transverse plane. Rigidly mounted within thebore of collar 56 and extending on either side thereof is a shaft 58.Two threaded guide members 60 are mounted at re' spective ends of shaft58 in a perpendicular direction thereto and are secured to shaft 58 withfastening means such as nuts 62. Guide members 60 slidably engage frontpanel 46 and back panel 47 of housing 12 for maintaining axial alignmentbetween coupling member 50 and piston 28 in a second transverse plane,which is perpendicular to the aforementioned first transverse plane,during the longitudinal movement of coupling member 50 and piston 28.

Coupling member 50, and consequently piston 28, is urged in a forwardlongitudinal direction, indicated by an arrow 63, by two elongatedhelical springs 64 and 66. The forward ends of both spring 64 and spring66 engage an anchoring member such as, for example, eye bolts 68. Bolts68 are, in turn, fixedly mounted on forward end 42 of housing 12. Therearward end of springs 64 and 66 are rigidly secured to base 54 withmeans such as couplings 70. Thus, as springs 64 and 66 compress, piston28 is urged into container 22 to force fluid out through the hypodermicneedle.

Coupling member 50 includes along its midportion a rack 72 integraltherewith, Engaging rack 72 is a pinion 73 mounted on and integral withthe end of main shaft 74 which extends outwardly from a mechanicaltiming mechanism 75. Timing mechanism 75 is a conven' tional, manuallywound time piece which includes a main spring 76 that conventionallyoperates or rotates a gearing mechanism 78 at a rate controlled by anescapement mechanism, generally shown at 80 in a manner that is wellknown in the art. Main spring 76 of timing mechanism 75 is manuallywound by the rotation of winding screw 82, shown in FIG. 1. As is shownin FIG. 1, winding screw 82 is accessible from the exterior of housing12 and is conveniently recessed in front panel 46. In another embodimentas shown in FIG. 2, screw 82 (not shown in the figure) is recessed inback panel 47.

In operation, fluid infusion apparatus 10 can be used to inject heparin,a drug which prevents blood clotting and is intraveneously administeredover an extended period of time to patients who have had, for example, apulmonary embolas. If fluid infusion apparatus 10 is of the reusabletype. a prefilled syringe is mounted onto the housing 12 subsequent tothe positioning of cou' pling member 50 in its most rearward position,as shown in FIG. 2. This is accomplished by rotating winding screw 82,and consequently pinion 73, which in turn, longitudinally positions rack72 and coupling member 50. The hypodermic needle of syringe 14 is theninserted into the vein of the patient at an appropriate location, suchas in the arm, and fluid infusion apparatus 10 is mounted on the arm bymeans of strap 20. Mechanical timing mechanism 75 is selected such thatpinion 33 will permit the full longitudinal travel of coupling member 50in the time period desired to administer the drug.

A second embodiment of a fluid infusion device according to theinvention, denoted 90, is shown in FIG. 5 and is similar to fluidinfusion device 10 described hereinabove, except that it furtherincludes an elapsed time and expended fluid indicator. Fluid infusiondevice includes a mechanical timing mechanism 91 which is similar tomechanical timing mechanism 75 shown in FIGS. 2, 3 and 4 and alsodescribed hereinabove, However, mechanical timing mechanism 91 includesa main shaft 92 which extends completely through the housing 93 of fluidinfusion device 90, and a pinion 94 mounted on main shaft 92 at themiddle portion thereof. Located at one end of main shaft 92 is a windingscrew 96, shown in phantom, for winding mechanical timing mechanism 90,and located at the other end of main shaft 92 is an indicator gauge 98that is mounted on the exterior of housing 93. Gauge 98 has a pointer100 which is connected by reduction gears 102 to main shaft 92 androtated thereby. indicia on the face of gauge 98 indicates elapsed timein two hour increments at an outer ring 104 and expended solution incubic centimeters at an inner ring 106. Thus, me chanical timingmechanism 91 can be wound by winding screw 96 to any desired timeindicated by gauge 98. Furthermore, the amount of the fluid which hasbeen injected and the elapsed time since the injection has started, orthe time remaining to complete the injection, can be readily and easilydetermined by reading gauge 98.

It is apparent from the foregoing that the fluid infusion apparatus ofthis invention supplies a constant feeding of a therapeutic fluid in acontrollable amount of flow over an extended period oftime. Otherembodiments of the invention can provide for an automatic, periodic,intermittent, infusion of a fluid contained within the syringe, or for amanually controllable inter mittent infusion of the fluid. Furthermore,still another embodiment of the invention can provide for a variableflow rate of the fluid.

Although the invention has been described in detail with respect to anexemplary embodiment thereof, it will be understood by those of ordinaryskill in the art that variations and modifications may be effectedwithin the scope and spirit of the invention.

I claim:

1. Portable, automatic fluid infusion apparatus for administering apredetermined amount of fluid at a predetermined rate over an extendedtime period, the device comprising an elongate housing attachable to auser;

a syringe mounted at one end of said housing in axial alignmenttherewith said syringe comprising an elongated container having anorifice through one end thereof and a piston mounted for longitudinalmovement within said container for forcing fluid through the saidorifice;

a mechanical power means coupled to and in axial alignment with saidpiston for longitudinally mov-- ing said piston, said power meansincluding rack means;

a mechanical timing mechanism mounted on said housing and coupled tosaid power means fo per mitting only a predetermined rate oflongitudinal movement of said piston by said power means,

thereby providing a predetermined flow of said fluid from said syringe,said mechanical timing mechanism including a main spring, an escapementmechanism, gearing mechanism connected to and rotated by said mainspring, said escapement mechanism permitting a controlled rate ofrotation of said gearing mechanism, a rotatable main shaft extendingoutwardly from said gearing mechanism and rotated thereby, said mainshaft having a pinion mounted at the outwardly extending end thereof andin engagement with said rack means, and means for winding said mainspring;

a first centering means transversely rigidly mounted on said rack meansfor bearing against opposite sides of said housing during thelongitudinal movement of said rack means for maintaining the axialalignment of said rack means and said piston in a first, transverseplane;

a second centering means transversely, rigidly mounted bn said rackmeans perpendicular to said first centering means for bearing against atleast one further side of said housing, other than said opposite sides,during the longitudinal movement of said rack means for maintaining theaxial alignment of said rack means and said piston in a second,transverse plane, said second transverse plane being perpendicular tosaid first transverse plane; and

a helical spring attached at a first end to the end of said housing atwhich said syringe is mounted and attached at the other end to saidfirst centering means for longitudinally urging said rack means intoengagement with said piston for the longitudinal movement thereof, saidpinion of said mechani cai timing mechanism restraining the longitudinalmovement of said rack means to a predetermined rate determined by therotational speed of said pinion. and thereby permitting a predeterminedamount of fluid to be forced by said piston through said orifice duringa predetermined time.

2. Fluid infusion apparatus as claimed in claim 1 wherein said syringeis removably mounted at one end of said housing in axial alignmenttherewith, and said power means is mounted within and totally enclosedby said housing in axial alignment with said piston of said

1. Portable, automatic fluid infusion apparatus for administering apredetermined amount of fluid at a predetermined rate over an extendedtime period, the device comprising an elongate housing attachable to auser; a syringe mounted at one end of said housing in axial alignmenttherewith said syringe comprising an elongated container having anorifice through one end thereof and a piston mounted for longitudinalmovement within said container for forcing fluid through the saidorifice; a mechanical power means coupled to and in axial alignment withsaid piston for longitudinally moving said piston, said power meansincluding rack means; a mechanical timing mechanism mounted on saidhousing and coupled to said power means for permitting only apredetermined rate of longitudinal movement of said piston by said powermeans, thereby providing a predetermined flow of said fluid from saidsyringe, said mechanical timing mechanism including a main spring, anescapement mechanism, gearing mechanism connected to and rotated by saidmain spring, said escapement mechanism permitting a controlled rate ofrotation of said gearing mechanism, a rotatable main shaft extendingoutwardly from said gearing mechanism and rotated thereby, said mainshaft having a pinion mounted at the outwardly extending end thereof andin engagement with said rack means, and means for winding said mainspring; a first centering means transversely rigidly mounted on saidrack means for bearing against opposite sides of said housing during thelongitudinal movement of said rack means for maintaining the axialalignment of said rack means and said piston in a first, transverseplane; a second centering means transversely, rigidly mounted on saidrack means perpendicular to said first centering means for bearingagainst at least one further side of said housing, other than saidopposite sides, during the longitudinal movement of said rack means formaintaining the axial alignment of said rack means and said piston in asecond, transverse plane, said second transverse plane beingperpendicular to said first transverse plane; and a helical springattached at a first end to the end of said housing at which said syringeis mounted and attached at the other end to said first centering meansfor longitudinally urging said rack means into engagement with saidpiston for the longitudinal movement thereof, said pinion of saidmechanical timing mechanism restraining the longitudinal movement ofsaid rack means to a predetermined rate determined by the rotationalspeed of said pinion, and thereby permitting a predetermined amount offluid to be forced by said piston through said orifice during apredetermined time.
 1. Portable, automatic fluid infusion apparatus foradministering a predetermined amount of fluid at a predetermined rateover an extended time period, the device comprising an elongate housingattachable to a user; a syringe mounted at one end of said housing inaxial alignment therewith said syringe comprising an elongated containerhaving an orifice through one end thereof and a piston mounted forlongitudinal movement within said container for forcing fluid throughthe said orifice; a mechanical power means coupled to and in axialalignment with said piston for longitudinally moving said piston, saidpower means including rack means; a mechanical timing mechanism mountedon said housing and coupled to said power means for permitting only apredetermined rate of longitudinal movement of said piston by said powermeans, thereby providing a predetermined flow of said fluid from saidsyringe, said mechanical timing mechanism including a main spring, anescapement mechanism, gearing mechanism connected to and rotated by saidmain spring, said escapement mechanism permitting a controlled rate ofrotation of said gearing mechanism, a rotatable main shaft extendingoutwardly from said gearing mechanism and rotated thereby, said mainshaft having a pinion mounted at the outwardly extending end thereof andin engagement with said rack means, and means for winding said mainspring; a first centering means transversely rigidly mounted on saidrack means for bearing against opposite sides of said housing during thelongitudinal movement of said rack means for maintaining the axialalignment of said rack means and said piston in a first, transverseplane; a second centering means transversely, rigidly mounted on saidrack means perpendicular to said first centering means for bearingagainst at least one further side of said housing, other than saidopposite sides, during the longitudinal movement of said rack means formaintaining the axial alignment of said rack means and said piston in asecond, transverse plane, said second transverse plane beingperpendicular to said first transverse plane; and a helical springattached at a first end to the end of said housing at which said syringeis mounted and attached at the other end to said first centering meansfor longitudinally urging said rack means into engagement with saidpiston for the longitudinal movement thereof, said pinion of saidmechanical timing mechanism restraining the longitudinal movement ofsaid rack means to a predetermined rate determined by the rotationalspeed of said pinion, and thereby permitting a predetermined amount offluid to be forced by said piston through said orifice during apredetermined time.